The present invention relates to refrigeration or cooling systems. More particularly, the present invention relates to a batch freezing process of and a hatch freezer for making custard, ice cream, or other frozen food stuff.
Ice cream or frozen custard machines, as well as other systems for cooling or freezing food stuffs, condiments, or other materials, typically include an evaporator situated proximate the material being chilled. For example, in ice cream machines, liquid ice cream (e.g., the mix) is typically inserted in a freezing chamber or barrel associated with the evaporator and is removed from the barrel as solid or semi-solid ice cream. The evaporator removes heat from the freezing chamber as a liquid refrigerant, such as, FREON(copyright), ammonia, R-404a, HP62, or other liquid having a low boiling point, changes to vapor in response to the heat from the liquid ice cream. Typically, the evaporator is partially filled with vapor as the liquid refrigerant boils (e.g., becomes vapor) in the evaporator.
Since most heat transfer occurs when the liquid refrigerant is changed to vapor, the partially filled evaporator is less efficient than a flooded evaporator (e.g., an evaporator filled entirely with liquid refrigerant). The partially filled evaporator also tends to unevenly cool the ice cream because the parts of the evaporator which are filled with vapor are not able to cool as effectively as the parts of the evaporator filled with liquid. Further, prior art ice cream machines are disadvantageous because the temperature does not remain constant in the evaporator due to the accumulation of vapor. The inefficiencies resulting from the partially filled evaporator require a larger, more expensive, and less energy-efficient compressor. The goal of an efficient evaporator is to reduce the quantity of vapor in the barrel to optimize the surface area for liquid refrigerant evaporation. Although there is always a quantity of vaporized refrigerant in the barrel it is essential to minimize stagnation of the vapor within the heat exchange area. By reducing the stagnation of the vaporized refrigerant within the barrel, there is a more efficient transfer of heat. There can be a closer relationship of refrigerant evaporating temperature to ice cream or frozen custard freezing temperature. A result of this closer temperature difference is higher compressor efficiency.
In addition, custard or ice cream quality and efficient manufacture of such custard or ice cream are dependent upon maintaining a constant evaporator temperature (e.g., constant barrel temperature). The barrel temperature must be kept in a proper range for making custard or ice cream so the custard or ice cream. If the custard or ice cream is allowed to become too cold, the mix or liquid ice cream in the evaporator becomes highly viscous and can block the travel of the ice cream through the barrel. Blockage of the barrel in the freezing process is commonly known as xe2x80x9cfreeze upxe2x80x9d.
Maintaining the temperature of the barrel at a constant level is particularly difficult, as ice cream flow rates through the machine vary and change the cooling load on the evaporator. For example, more heat dissipation is required as more ice cream is produced (i.e., the flow rate is increased). Additionally, if the barrel temperature is too low, refrigerant flood-back problems can adversely affect the operation of the compressor. For example, if the refrigerant is not fully evaporated as it reaches the compressor, the liquid refrigerant can damage the compressor.
Batch freezing processes and batch freezing systems are often utilized to produce large quantities of frozen food stuffs, such as frozen custard or ice cream. Batch freezing systems can meet a demand of approximately up to 100 to up to 900 servings per hour. Such processes and systems can meet the needs of a single store or stand or be part of a large production operation for multi-store operations.
Conventional batch freezing processes typically utilize a conventional refrigerated barrel-type ice cream maker and a freezing cabinet. The conventional refrigerated barrel utilizes a smooth tube surrounded by refrigeration coils, (e.g., copper tubes wrapped around the smooth tube). For the reasons discussed, such conventional refrigerated barrels are inefficient and do not evenly chill the ice cream as quickly as possible, thereby failing to produce the highest quality ice cream.
In a conventional process, a mix of custard or ice cream is driven through the barrel via an auger. The mix remains in the barrel until it begins to freeze and reaches a xe2x80x9cslurryxe2x80x9d form (at a temperature of 22xc2x0 F.). Conventional systems generally require about 10 to 12 minutes to freeze the mix into the slurry form. Once the slurry form is achieved, the mix exits the barrel and falls into (is caught) in a freezing container or bucket. The freezing container is placed in a freezing cabinet where it is brought from a temperature of about 22xc2x0 F. to about xe2x88x925xc2x0 F. The ice cream or custard ripens or is brought to its final temperature in the freezing cabinet.
Thus, there is a need for a batch ice cream machine. Further still, there is a need for a batch process which can more efficiently and more evenly cool ice cream or custard. Even further still, there is a need for a batch freezer or batch process which utilizes a single barrel and yet produces high quality or premium custard and ice cream more quickly.
An exemplary embodiment relates to a batch freezing ice cream making system. The batch freezing ice cream making system includes an evaporator, a compressor, and a condenser. The evaporator has a refrigerant input and a refrigerant output. The evaporator has an exterior surface and an interior surface. The interior surface defines a cooling chamber, and the exterior surface and the interior surface define an evaporator chamber. The cooling chamber has an ice cream input and an ice cream output. The evaporator chamber is flooded with liquid refrigerant. The compressor has a compressor input and a compressor output. The compressor input is coupled to the refrigerant output. The condenser has a condenser input and a condenser output. The condenser input is coupled to the compressor output, and the condenser output is coupled to the refrigerant input.
Another exemplary embodiment relates to a batch process for making ice cream. The batch process includes chilling a mix in a flooded evaporator and placing the mix in a freezer when the mix reaches a particular consistency. The flooded evaporator has an interior surface defining an interior cooling chamber.
Still another exemplary embodiment relates to a batch frozen custard making system. The batch frozen custard making system includes a freezer and an evaporator system. The evaporator system has an evaporator input and an evaporator output. The evaporator system also has an interior surface defining a cooling chamber. The evaporator system maintains a liquid refrigerant about the cooling chamber. A bucket is filled with the contents of the cooling chamber and placed in the freezer.